During auroral substorms, active auroras involving field-aligned electric fields appear at the poleward border of the auroral oval. Equatorward of these active discrete auroras, a diffuse region of luminosity develops which often features imbedded localized structures which can have distinctively north-south orientations. In this paper we study the behaviour of such longitudinally confined north-south oriented auroral arc structures which may turn on and off sporadically during the substorm lifetime. In particular, we show observations which suggest that these structures may be the projection on the ionosphere of the drift paths of energetic electrons as they drift from the magnetotail into the more dipolar inner magnetosphere. Our results suggest that injection of auroral particles into the central plasma sheet occurs in quite localized regions over lengthy periods of time. The injected particles drift earthward in the central plasma sheet where those electrons with pitch angles close to the loss cone are sporadically caused to precipitate into the ionosphere causing the fingers of luminosity. North--south aligned structures near the equatorward edge of the oval are believed to represent precipitation of a spatially localized population of energetic electrons for which the westward convective drift velocity in the evening sector nearly balances the eastward gradient and curvature drift velocity thus leading to purely earthward convective drift of the energetic electrons. ¿American Geophysical Union 1987